U.S. patent number 4,355,638 [Application Number 06/100,513] was granted by the patent office on 1982-10-26 for infusion apparatus.
This patent grant is currently assigned to Josef Hirschmann. Invention is credited to Josef Hirschmann, Peter Iwatschenko.
United States Patent |
4,355,638 |
Iwatschenko , et
al. |
October 26, 1982 |
Infusion apparatus
Abstract
The disclosure concerns a gravity operated infusion apparatus. A
solvent container is suspended above an infusion needle. A flexible
tube joins the container and needle. A tube clamp varies the
cross-section of the tube for controlling the infusion rate.
Between the tube clamp and the needle an additional pressing
apparatus is selectively actuable for increasing the pressure
within the tube and between the tube clamp and infusion needle. In
one embodiment the pressing apparatus comprises an eccentric disc
that cooperates with a plate for pressing the tube and in another
embodiment two plates are squeezed together against the tube. In a
modification embodiment one plate rocks or tumbles as it moves with
respect to the other plate.
Inventors: |
Iwatschenko; Peter
(Neunkirchen, DE), Hirschmann; Josef (8021 Neuried,
DE) |
Assignee: |
Hirschmann; Josef
(DE)
|
Family
ID: |
6056714 |
Appl.
No.: |
06/100,513 |
Filed: |
December 5, 1979 |
Foreign Application Priority Data
Current U.S.
Class: |
604/65;
128/DIG.12; 604/153; 604/250 |
Current CPC
Class: |
A61M
5/1689 (20130101); Y10S 128/12 (20130101) |
Current International
Class: |
A61M
5/168 (20060101); A61M 005/00 () |
Field of
Search: |
;128/214,214E,214F,DIG.12,DIG.13 ;417/478-480 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pellegrino; Stephen C.
Attorney, Agent or Firm: Ostrolenk, Faber, Gerb &
Soffen
Claims
We claim:
1. Infusion apparatus operable by gravity, and comprising:
a solvent container for being suspended at a higher level than the
infusion point; a drop chamber means beneath the container and
connected to the container for infusion to drop through;
an infusion needle; an infusion tube connecting the drop chamber
means and the needle, the infusion tube being clampable for
changing the cross-section thereof;
a tube clamp means connected on the tube for clamping the tube to
vary the cross-section thereof to a selected cross-section for
controlling the normal gravity flow infusion rate;
pressure increasing means connected externally of the tube at a
portion of the tube between the tube clamp means and the needle;
the pressure increasing means being selectively actuated in
response to predetermined flow conditions in said tube for
periodically increasing the pressure in the section of the tube
between the tube clamp means and the needle and for thereafter
permitting the pressure in that section of the tube to decrease by
compressing and then releasing the tube at spaced time
intervals.
2. The infusion apparatus of claim 1, wherein at the portion of the
tube at the pressure increasing means, the tube is resiliently
formed and the pressure-increasing means comprises pressing means
for controllably compressing the tube portion for producing
pressure fluctuations in the tube.
3. Infusion apparatus operable by gravity, and comprising:
a solvent container for being suspended at a higher level than the
infusion point; a drop chamber means beneath the container and
connected to the container for infusion to drop through;
an infusion needle; an infusion tube connecting the drop chamber
means and the needle, the infusion tube being clampable for
changing the cross-section thereof;
a tube clamp means connected on the tube for clamping the tube to
vary the cross-section thereof to a selected cross-section for
controlling the normal gravity flow infusion rate;
pressure increasing means connected externally of the tube at a
portion of the tube between the tube clamp means and the needle;
the pressure increasing means being selectively actuated in
response to predetermined flow conditions in said tube for
periodically increasing the pressure in the section of the tube
between the tube clamp means and the needle and for thereafter
permitting the pressure in that section of the tube to decrease by
compressing and then releasing the tube at spaced time
intervals;
at the portion of the tube at the pressure increasing means, said
tube being resiliently formed and the pressure increasing means
comprising pressing means for controllably compressing the tube
portion for producing pressure fluctuations in the tube;
said pressing means comprising two plates between which the tube
portion passes;
and means for driving the plates toward and away from one another
for selectively compressing and then releasing the tube at spaced
time intervals.
4. The infusion apparatus of claim 2, wherein the plates are
oriented parallel to each other and the driving means drive the
plates toward and away from one another generally along a direction
perpendicular to the planes of the plates.
5. The infusion apparatus of either of claims 3 or 4, wherein the
frequency of the driving movement of the plates toward one another
is variable for varying the time under which the tube is
pressurized.
6. The infusion apparatus of either of claims 3 or 4, wherein the
amplitude of the driving movement of the plates toward one another
is variable for varying the pressure in the tube.
7. The infusion apparatus of claim 3, wherein the plates connected
to the drive means are interchangeable for others of the plates
that are sized for contacting a different size area of the
tube.
8. The infusion apparatus of claim 3, wherein the drive means for
the plates comprises an electromagnet drive means.
9. The infusion apparatus of claim 3, wherein the drive means for
the plates comprises an electric motor connected with the plates
for moving the plates toward and away from one another.
10. The infusion apparatus of either of claims 2 or 3, wherein the
tube portion contacted by the pressure increasing means is
comprised of silicone rubber, and the remainder of the tube is
comprised of a PVC flexible tube; and the silicone rubber and PVC
portions of the tube are of the same cross-section.
11. The infusion apparatus of either claims 2 or 3, wherein the
tube portion contacted by the pressing means is of a different
cross-section than the remainder of the tube.
12. The infusion apparatus of claim 3, wherein the tube portion for
being contacted by the pressing means is separate from the infusion
tube and is connected with the infusion tube by a branch
member.
13. The infusion apparatus of either claims 1 or 3, further
comprising means for constricting the cross-section of the tube and
located between the pressure increasing means and the drop
chamber.
14. The infusion apparatus of either claims 1 or 3, further
comprising a detector for measuring the rate of infusion of the
tube and the detector generating an output signal; means connecting
that output signal to the pressure increasing means for controlling
the pressure increasing means.
15. The infusion apparatus of either of claims 1 or 3, wherein the
pressure increasing means operates to produce cyclic pressure
fluctuations.
16. The infusion apparatus of any of claims 1, 2 or 3, wherein the
tube between the pressure increasing means and the needle is opened
for not blocking return of any fluid in the tube in the direction
past the pressure increasing means toward the tube clamp upon the
pressure increasing means selectively not applying pressure to the
tube portion.
17. The infusion apparatus of claim 14, wherein the tube between
the pressure increasing means and the needle is opened for not
blocking return of any fluid in the tube in the direction past the
pressure increasing means toward the tube clamp upon the pressure
increasing means selectively not applying pressure of the tube
portion.
18. The infusion apparatus of claim 1 or 2, wherein the pressure
increasing means is formed by pressing means controllably
compressing a resiliently formed portion of the tube for producing
pressure fluctuations in the tube, said pressing means being formed
by a substantially circular concave support plate on which said
portion of said tube bears and opposite said tube there is an
eccentric means which presses said portion of said tube against the
plate.
19. The infusion apparatus of claim 18, wherein the eccentric means
is formed by an eccentrically mounted roller means on the outer
periphery of which a slide ring is disposed, and wherein the latter
is rotatable with respect to the eccentrically mounted roller means
and presses the tube portion against the plate.
20. The infusion apparatus of claim 1, wherein the pressing
apparatus is formed by two plates between which said portion of
said tube is passed, at least one of said plates being driveable
towards the other of said plates, and said at least one of said
plates performs a tumbling movement relative to said other of said
plates and in the direction towards said other of said plates.
Description
The invention relates to an infusion apparatus operating by the
gravity principle and comprising a solvent container which is
suspended at a higher level than the infusion point and to which a
drop chamber is connected which is connected via an infusion
flexible tube to an infusion needle, and a tube clamp for varying
the cross-section of the flexible tube for controlling the infusion
rate.
In gravity infusion the pressure for the solution to be infused is
produced by the weight of the solution itself. In practice, this is
effected by suspending the solvent container higher than the
infusion point with the infusion cannula. The pressure produced or
increased by gravity of about 0.15 bar =1500 mm water column
overcomes the counter pressure of the body of about 80 mm water
column and infuses the fluid. The magnitude of the pressure depends
on the height of suspension of the solvent container.
When the fluid in the solvent container is nearly exhausted and the
pressure in the fluid drops to the counter pressure of the body,
the infusion ceases. A liquid column corresponding to the body
counter pressure remains to ensure that no air is infused.
The infusion rate is adjusted in the simplest manner with a tube
clamp or, when higher demands are made, with a control means for
controlling the infusion rate which also effects a compression and
reduction of the cross-section of the infusion tube.
Due to the principle of producing the pressure necessary for the
infusion by gravity, in the aforementioned manner it is not
possible for an inadmissibly high pressure to arise and on the
other hand the pressure drops automatically when the supply of
infusion solution approaches its end and air enters the infusion
fittings.
For special applications, for example infusions into the thin blood
vessels of children, infusion with elevated pressure is however
necessary. Ordinary pump means cannot be used for this purpose
because there is a danger that air will be infused when the solvent
container is emptied.
The problem underlying the invention is to provide an infusion
apparatus of the type mentioned at the beginning with which it is
possible to increase the infusion pressure without any danger of
infusion of air.
This problem is solved by the invention set forth in claim 1.
Further advantageous developments and embodiments of the invention
are apparent from the subsidiary claims.
The construction of the infusion apparatus according to the
invention makes it possible to increase the infusion pressure
without any danger of the infusion of air because in the infusion
flexible tube only periodic pressure fluctuations are produced
which with a tube filled with air can readily compensate each other
so that when an air column occurs between infusion point and
pressing means there is still an adequate fluid column before the
infusion point.
An advantageous application of the infusion apparatus according to
the invention is in conjunction with control means which are
adjustable to a desired infusion rate and which open a tube clamp
to a varying degree in dependence upon the number of drops falling
through the drop chamber. If when using such control infusion means
blockage of the infusion needle or constriction of its effective
cross-section occurs, the control means adjusts the tube clamp to
the largest opening and then detects that even in this position of
the clamp no drop passes through. The control means may be so
constructed that when this condition occurs, which is an alarm
condition, said means completely closes the tube clamp and drives
the control means of the pressing means so that pressure
fluctuations are produced thereby in the liquid column between the
tube clamp and the infusion needle which in most cases remove
stoppages or constrictions of the outlet cross-section. The
pressure generation may preferably be in several stages, for
example three. The tube portion is compressed to various extents,
although even at full pressure generation a fluid passage remains
for pressure compensation. These three stages of the compression
can be produced successively, the tube clamp being reopened after
each stage and a determination made whether a drop falls in the
drop chamber in appropriate time.
If the check result is negative the control means switches the
pressing means to the next highest stage of the pressure generation
whereas if it is positive the control means can switch back to the
next-lowest stage.
Thus, with brief closures of the infusion channel the entire
infusion apparatus thereafter automatically returns to gravity
operation but oscillates permanently between the various pressure
generation stages when permanent pressure support is necessary to
obtain the desired infusion rate.
The invention will be explained hereinafter with reference to the
examples of embodiment illustrated in the drawings, wherein:
FIG. 1 shows a known embodiment of an infusion apparatus operating
by the gravity principle;
FIG. 2 shows an embodiment of the infusion apparatus according to
the invention;
FIG. 3 shows an embodiment of the pressing means for increasing the
pressure;
FIG. 4 shows a further embodiment of a pressing means for
increasing the pressure.
FIG. 5 shows a third embodiment of a pressing means for increasing
the pressure.
FIG. 1 illustrates a known infusion apparatus operating by the
gravity principle. This infusion apparatus comprises a solvent
container 1, a drop chamber 2, an infusion flexible tube 3 and an
infusion needle 4. This infusion apparatus is also provided with a
control means for regulating the infusion rate which includes a
drop sensor 5 and a tube clamp 7 controlled via an electronic
control means 6. The cross-section of the tube 3 in the region of
the clamp 7 is adjusted to the desired value by the control means 6
in dependence upon the drops falling through the drop chamber
2.
In simpler infusion means of this type the tube clamp 7 is adjusted
manually to a value obtained empirically or by experience.
However, with temporary high counter pressure at the infusion point
or in the case of infusion into very narrow blood vessels falling
of the drop through the drop chamber 2 can be prevented. To obviate
this disadvantage, in the embodiment illustrated in FIG. 2 a
pressing means 9 is provided which permits compression of the tube
between the tube clamp 7 and the infusion point 4 so that in this
region of the tube the pressure is increased. In the normal case,
the infusion means operates with the pessure generated by gravity.
However, if this pressure is not adequate the pressing means 9 with
the aid of the control means 8, either by manual control or
controlled by a usual control means 6, can produce individual or
periodic pressure fluctuations in the region of the tube between
the clamp 7 and the infusion needle 4. For this reason, in the
region of the tube 3 between the drop chamber 2 and the pressing
means 9 either a check valve may be provided or a means reducing
the cross-section of the tube; alternatively, the clamp 7 actuated
by the control means 6 can be utilized for this purpose. For
independent operation without a control means 6 the pressing means
9 can be periodically compressed by the control means 8 so that a
pulsating pressure oscillation of the liquid column results in the
infusion tube, the fluid thereby being conveyed out of the solvent
container to the patient.
When the control means 6 are employed, said means determine with
the aid of a drop sensor 5 whether or not a drop falls in the drop
chamber. The tube clamp 7 is opened by said control means to a
varying degree in dependence upon the desired number of drops per
unit time and thus the infusion rate. If due to stoppage or
constriction of the infusion channel no drops or inadequate drops
per unit time fall through the drop chamber the control means 6
drives the control means 8 and the portion of the tube in the
pressing means 9 is thereby compressed, the resulting pressure
increase causing the infusion fluid to emerge through the infusion
needle 4. Before compression of the tube the control means 6 acts
on the clamp 7 so that the cross-section of the tube is greatly
reduced at least in the region of said clamp 7, if not closed
completely.
As long as fluid is present in the tube 3 the compression of the
tube portion in the pressing means 9 produces excess pressure in
the system which however is limited by the elasticity of the tube.
If air enters the system, it can be compressed and the pressure
rises only slightly. By dimensioning the pressing means, in
particular the length of the portion of the tube compressed by the
pressing means 9 between the clamp 7 and the infusion needle 4, the
maximum pressure which arises when air enters the system is fixed.
The pressure can thus be limited so that it definitely remains
below the body counter pressure and air infusion is impossible.
The maximum pressure arising in the flexible tube 3 is limited
either by elasticity of the tube or by limiting the force on the
pressing means 9.
The pressing means 9 is controlled in dependence upon tne number of
drops falling through the drop chamber 2 and the position of the
clamps 7 and infusion amount to be delivered.
Examples of embodiment of the pressing means are explained
hereinafter with reference to FIGS. 3 through 5.
The embodiment of the pressing means illustrated in FIG. 3 consists
of a substantially circular concave support plate 12 on which the
portion of the tube rests, an eccentric disc 10 pressing via a
slide ring 11 on said tube portion. By adjustment of the distance
between the plate 12 and the axis of the eccentric disc 10
adjustment of the maximum pressure increase is possible and the
speed of rotation of the eccentric disc 10 driven by rotating motor
means (not shown) determines the frequency of the pressure
fluctuations per unit time. With continuous rotation of the
eccentric in this manner periodic pressure fluctuations may be
obtained in the liquid column.
In the embodiment of the pressing means in FIG. 4 the portion of
the tube 3 disposed between two plates 13, 14 and the plate
designated by 14 can be pressed via springs 15 with the aid of a
drive means not shown against the plate 13 to compress the tube.
The drive means in this case can be formed by an electromagnet or
an electric motor. The force is limited by the spring elements 5 at
the pressure jaws or by limiting the power of the drive member.
Further limitation results from the elasticity of the tube as
described above.
FIG. 5 shows an embodiment of the pressing means which is similar
to the embodiment of FIG. 4, but wherein one plate 14a is subjected
to a tumbling movement by means of a mechanism 8a which forms part
of the control means 8 shown in FIG. 2; The mechanism 8a includes a
crank disc (8b) which may selectively be driven into rotation by
motor means not shown and drives a connecting rod 8c which is
rigidly connected to plate 14a at the center thereof. The center of
plate 14a further is guided along to dashed straight line 14b
perpendicular to the plane of the front surface of plate 13a in
contact with the tube 3. Therefore plate 14a performs a tumbling
movement wherein at a first instant only the upper half of the
plate comes into contact with the tube 3 compressing it to a
continuously greater extent until plate 14a is parallel to plate
13a. Thereupon the upper half of plate 14a moves from tube 3
leaving the lower half of plate 14a in engagement with tube 3.
Finally plate 14a is completely withdrawn from tube 3.
By the tumbling movement of plate 14a a soft and continuous
increase of the pressure within tube 3 is obtained. The mechanism
8a of course may be replaced by other mechanism known in the art
for obtaining said tumbling movement. Of course, other embodiments
of the processing means are conceivable because the only important
point is that a certain portion of the tube is briefly or
periodically compressed. Furthermore, it is not necessary for the
tube 3 to form a continuous part with the compressed portion; said
portion can firstly consist of material different to that of the
remaining tube 3, for example of silicone rubber, and secondly said
portion may have a different cross-sectional form or different
cross-sectional area than the remaining tube 3, depending on the
desired pressure increase.
It is further possible to make the compressed tube portion as
separate portion which is connected to the actual infusion tube 3
via a branching.
When using the pressing means 9 and the associated control means 8
in conjunction with an infusion system having a control means 6
according to FIG. 2 the pressure may be generated in a plurality,
for example three, of stages, in each of which the tube portion is
compressed to a different extent. Even with full pressure
generation a fluid passage remains in the tube portion at the
compressed point for pressure compensation.
If the control means 6 establishes that support pressure is
required the clamp 7 is closed. Thereafter, the pressing means 9 is
driven with the aid of the control means 8 so that the first stage
of compression of the tube portion results, whereupon the pressing
means returns to the starting or rest position. The control means 6
then again checks by opening the clamp 7 whether infusion fluid can
flow. If this is not the case, the next stage of compression of the
tube portion is initiated. Thereafter, a check is again made
whether fluid can flow. If the result of this check by the control
means is negative, i.e. adequate dripping in the drop chamber is
not detected or there is no output signal from the drop sensor, the
next highest stage of the pressing means 8 is switched on. If the
check remains negative even with the highest pressure stage the
apparatus initiates an alarm.
If with the aid of the drop sensor 5 the control means 6 detects
that drops are falling through the drop chamber and solution thus
flowing, it switches back one stage in the following pressure
support of the pressing means 8. Consequently, in the case of brief
closures of the infusion passage the system automatically returns
to pure gravity operation. When pressure support is continuously
necessary, however, the system permanently oscillates between the
stages of the pressing means 9.
The embodiments of the pressing means illustrated in FIGS. 3
through 5 represent only advantageous ones.
Further advantageous embodiments can be obtained by using
magnetostrictive or electrostrictive elements for the plates 13, 14
or the plate 12 and the slide ring 11. In this case, the electric
motor or electromagnetic drive may be omitted so that no
mechanically driven elements are necessary.
* * * * *